Muffler



Dec. 8, 1931.

MUFFLER E. HUBY Filed Jan 9, 1929 IN VEN TOR.

T T ORNEY.

I Patented 8, 19 31 UNITED STATES mm HUBY, F PROVIDENCE, BHODE MUFFLERApplication Med January 9, 1828. Serial llo. 881,858.

M invention relates to improvements in mufiiers for internal combustionengines, particularly adapted for use in mufliing sound produced byautomobile, aeroplane and other types of internal combustion engines. Anobject of my invention is to substan-' tiallymufile both velocity andpressure pulsations in the exhaust from an internal combustion enginewithout causing any substantial amount of back pressure or causing aloss in power. As'the result of the back pressure being substantiallyeliminated, it is obvious that the improved mufiier also functions as apower increaser as it lowers the exhaust l5 pressure in the engine tosubstantially atmospheric and permits more explosive mixture to beintroduced when the inlet valves are opened, the device in this mannerfunctioning to lessen the knock in the engine and to minimize carbonformation as a further result of'the better scavenging of the exhaustgas from the cylinders.

I preferably divide the pulsating flow in the main exhaust stream,throttle and also preferably absorb pressure pulsations in one portionthereof and also preferably substantially convert the pressure energy ofthe other portion thereof into velocity energy, by increasing thevelocity thereof, entrain said throttle portion into said velocityincreased portion, preferably delivering the pulsations of saidthrottled portion to said velocity increased portion substantiallybetween the pulsations thereof and also preferably equalize the velocityof said combined portions, whereby pressure and velocity pulsations ofan acoustic nature are" substantially eliminated.

In my preferred embodiment I provide the usual exhaust pipe, a pressurepulsation absorbing chamber of substantial volume, throttling orificesconnecting said exhaust pipe and chamber. a'nozzle on the rear end ofthe exhaust pipe down stream of said throttling orifices, a convergingbypass exterior of said nozzle connecting said throttling orifices andsaid chamber to the rear end of said nozzle and a velocity equalizingpassage connected to the rear junction of the bypass. As statedhitherto, the frequency w of the pulsations in the bypass willpreferably permit them to be entrained between the pulsationsof thevelocity increased mains stream discharged rearwardly through thenozzle. In my preferred embodiment, the bypass preferably comprises aconverging cone connected to a pressure pulsation ahsorbing chamber ofsubstantial volume so that the pressure pulsations therein may besubstantially absorbed before dischar into .0 said main stream. Themufller is pre erably so constructed as to substantially dischar e thepulsations of the bypass stream into t e main stream between thepulsations thereof at the normal operating rates for a standard 05 typeof engine. In order that my improved mufller, however, may be employedon diflerent makes of engines operating at different cycles. Ipreferably provide means to regulate the velocity of the shunt bypassstream so that the pulsations thereof may be discharged into the mainstream below the nozzle intermediate the pulsations therein. Also inaddition to permit the pressure pulsation absorbing chamber to absorbthe pulsations in said bypass stream, I preferably additionally employan air vent in said pressure pulsating absorbing chamber and Ipreferably so construct my improved muffler that the air vent for saidchamber may also be adjustable to admit the desired amount of air toregulate the velocity of'the bypass stream for different makes ofengines in their actual operating range.

These and such other objects of my invention as may hereinafter appearwill be best understood from a description of the accompanying drawings,which illustrate an embodiment thereof.

In the drawings, Fig. 1 is a longitudinal sectional view of a mufilerconstructed in ac-.

cordance with my invention showing the means I additionally provide toattach the elongated Velocity equalizing passage to the frame of anautomobile.

Fi 2 is a cross sectional view taken along the line 2-2 of Fig. 1.

Fig. 3 is a cross sectionalview taken along the line3-3of Fig. 1.

In the drawings, wherein like characters of reference indicate likeparts throughout, 10

generally indicates an improved type of.

mufier constructed in accordance with the teachings of my invention.

When my invention is attached to an auto-. mobile the usual exhaust pipe12 is cut off at a point near the center of the automobile and myimproved mufiler attached thereto projecting rearwardly therefrom.

To provide the various bypass and pressure pulsation absorbing chambersof my invention, I preferably provide near the front 'end thereof acasing 14 having a closed front end 16 provided with a central hole 18for mounting-on said exhaust pipe 12 and a forwardly projectingcylindrical collar'20 provided with the set screw 22 for detachables-ecurement of said casing around said exhaust pipe. Said casing 14 isprovided with a substantially cylindrical front portion 24 providedpreferably with an externally threaded periphery 26 and radial air holes28 near the front end thereof for a purpose later to be described.Saidcasing 24-. is also pro- "-vided with a conical rear end 30gradually tapering to a restricted orifice 32, said conical portionforming a Venturi converging cone.

For a reason to be described, said casing is rovided with a conicalflange 34 prOJecting inwardly substantially centrally thereof from theinner periphery of the cylindrical portion 24 thereof and terminating ina restricted nozzle 36 of smaller diameter than and spaced forwardlyfrom said casing rear orifice 32. Said conical flange is preferablyprovided with the preferably equally spaced radial holes or throttlingorifices 38 therein s seed from the nozzle 36 thereof and adapttoreceive therein the rear end of the exhaust pipe 12 to form whenattached tosaid exhaust pipe a forward frustro-conical pressurepulsation absorbing chamber 40 in front of said throttling orifices 38and a rear hollow frustro-conical expansion chamber or bypass 42 leadingto said casing orifice 32 to p form a bypass from said throttlingorifices 38 to down stream of said nozzle 36, also pref- I so fardescribed consists in dividing the main eas es flow stream dischargedfrom the pipe 12, permitting. a portion thereof to flow directlyrearwardly through the nozzle 36 and the other portions to expandradially outwardly through the throttling orifices 38 into the bypass42. It is obvious that the pressure pulsations in the portion of saidstream expanding outwardly through said throttling orifices will besubstantially absorbed in the front end 44 of the bypass 42 and in'thepressure pulsation absorption chamber 40. The flow of the main streamhas its pressure energy substantially converted into a" velocity energythrough the medium of the velocity increasing nozzle 36. It is thusobvious that the main stream will flow with increased velocity and thatthe portion of the stream bypassed through the throttling orifices 38and bypass 42 will be entrained in said velocity increased stream downstream of said nozzle 36. It is also apparent that the internal pressurevariations within the nozzle 36 are greatly decreased through the mediumof the leakage outward through said throttling orifices 38 andsubsequent pressure absorption in the chambers 40 and 44. As explainedthe parts of my invention are preferably so constructed as to permit thepulsations of said throttled portion to be delivered to said velocityincreased main stream substantially between the pulsations thereof ,atthe normal operating rates of' the internal combustion engine.

In order that my invention may be attached to difierent types ofinternal combustion engines operating at different rates I preferablyprovide means to regulate the speed of the shunt bypass stream to permitthe pulsations thereof to be entrained in the main stream between thepulsations thereof below the nozzle 36. It is also desirable that the'pressure pulsation absorption chamber 40. in order that it may betterabsorb pressure pulsations, have a slight leak or air vent therein,which as shown discharges through the shunt bypass stream as saidpressure pulsating absorbing chamber is connected to said shunt stream.It is obvious that the means to provide a leakage in said pressurepulsating absorption chamber and the means to increase the velocity ofthe shunt stream may becombined into one, and I thus preferably makeanair vent or vents 28 in the front end of the casing. In order that saidair vent may be adjustable to regulate the speed of the shunt stream, Ipreferably provide mv improved mufier with an adjustable 1 ring 46threaded on the threaded peripherv 26 of said front casing-14 and I alsopreferably provide it with the air deflecting cone 48 on the front endthereof to guide air rearwardly andv radially inwards through saidcasing. air holes 28 as shown by the arrows. As said ring may beadjustably threaded on said casing, it is obvious that the size its ofthe air holes may be adjustably varied to correspondingly vary the speedof the shunt. stream.

I provide an elongated throat velocity equalizing passage 50 attached tosaid rear casing orifice 32. It is thus obvious that, in flowing throughsaid velocity equalizing pas-- sage, the velocity of the combinedportions, namely, the flow from the main stream and the bypass shuntstream may be substantially equalized, the velocity ulsations of anacoustic pature, thereby being substantially eliminated. Said chambermay be suitably secured to the automobile frame 60 by means of thesupporting bracket 62 projecting downwardly therefrom. v

I also preferably provide a novel type of a rear discharge end 52 for mymuflier, said end, as shown, preferably comprising the diverging cone 52preferably with the solid rear end 54. Said rear end 54 is provided withthe solid conev 56 projecting forwardly therefrom forming a flowsplitter and a plurality of axial air discharging holes 58 preferably ofa combined area greater than that of the equalizing passage 50 exteriorof said conical flow splitter 56. It is thus obvious that if any type ofpulsations remain at the end ofthe discharge through the equalizing pawle 50, there will be an even split rearward ow of the exhaust gasesthrough the small axial holes 56 which will function to sieve out anyremaining noise. It is understood that my invention is not limited tothe specific embodiments shown and methods described and that variousdeviations may be made therefrom without departing from the spirit andscope of the appended claims.

What I claim is:

1. A mufller for internal combustion engines, comprising a casing havinga closed front end provided with a central hole for an exhaust pipe anda forwardly projecting cylindrical collar for mounting thereof on saidexhaust pi and further having a substantially cylin rical front portionprovided with an externally threaded periphery and radial air holes nearthe front end thereof and a conical rear end gradually tapering to arestricted orifice forming a enturi converging cone, and a conicalflange projecting inwardly and rearwardly substantially centrally fromthe inner periphery of the cylindrical portion thereofterminating in arestricted nozzle of smaller diameter than and.

spaced from said casing rear orifice and having spaced radial holestherein aced from the nozzle thereof adapted to receive the rear end ofthe exhaust pi therein to form when attached to said ex aust pi aforward frusto conical pressure equalizing pulsation absorbing chamberin front of said holes and a rear hollow frusto-conical expansionchamber leading to said casing orifice, whereby the on the front endthereof to guide air radially inwards through said casing air holes, anelongated throat equalizing passage attached to said rear casing orificeand a Venturi diverging cone at the rear end thereof provided with asolid cone pro'ecting forwardly from the rear end thereof and aplurality of axial dischar e holes.

2. A muffler for internal combustion engines, comprising, a casinghaving a closed front end provided with a central hole for an exhaustpipe and a forwardly projecting cylindrical collar for mounting thereofon said exhaust ipe and further having a Sill)- stantially cylindricalfront portion and a conical rear end gradualh tapering to a restrictedorifice forming a enturi converging cone, and a conical flangeprojecting inwardly and rearwardly substantially" centrally from theinner periphery of the cylindrical portion thereof terminating in arestricted nozzle of smaller diameter than and spaced forward from saidcasing rear orifice and having spaced radial holes therein spacedforward from the nozzle"thereofadapted to receive the rear end of theexhaust pipe therein to form when attached to said exhaust pipe, aforward frusto covered pressure equalizing pulsation absorbing chamberin front of said holes and a rear hollow frnstoconical expansion chamberleading to said casing orifice, whereby the pulsatin flow from theexhaust stream may be bro (en to allowa portion thereof to flow directlyin pulsating manner through the nozzle and portions thereof to expandradially outwardly into said frusto-conical expansion chamber andcontact in the narrow rear end thereof intermediate the pulsations ofthe exhaust stream, an elongated throatequalizingpassage attached tosaid rear casing orifice and a Venturi diverging cone at the rear endthereof provided with a solid cone projecting forwardly from the rearend thereof and a plurality of axial discharge holes of a greatercombined area than said equalizing passage exterior of said cone.

3. In a mufiler, an .imperforate exhaust pipe, a casing having acontracting rear portion terminating in an,open end, a wall con tractingfrom substantially the center of said casing to an exhaust nozzle spacedforwardly from said open end having radial discharge ports therein andadapted to receive the exhaust pipe end and to form a bypass expansionand contraction chamber for a portionof the exhaust gases exteriorthereof and a front pressure pulsation absorption chamber interiorthereof, said wall being so shaped that the exhaust stream may be brokento allow a portion thereof to flow in pulsating manner through thenozzle and other pulsating portions thereof to expand radially outwardlyterior thereof and a front pressure ulsation absorption chamberinterior'thereo said exhaust pipe terminating substantially in the planeof said ports, said wall being so shaped that the exhaust stream may bebroken to allow a portion thereof to flow in pulsatin manner through thenozzle and other pu eating portions thereof to expand radially outwardlyinto and through said contracting bypass to join the other flow streamportion intermediate the pulsations thereof at the normal operatingrate.

5. In a mufiier, in combination, a non-restricting main flow passagehaving a nozzle therein, a contracting bypass therefor shaped to splitthe pulsations of the main flow stream and to permit the pulsating splitportions thereof to rejoin the main stream intermediate the pulsationsthereof at normal op erating rates beyond said nozzle to form a moresteady and even stream, and a pressure pulsation absorbing chamber ofsubstantial volume communicating with said bypass and having anadjustable air vent therein.

6. In a mufiier, in combination, a non-restricting main flow passage, abypass therefor and a pressure pulsation absorption chamber ofsubstantial volume communicating with said bypass having an adjustableair vent therein.

7 In a mufiier, in combination, a non-restricting exhaust pipe, apressure pulsation absorption chamber of substantial volume,

throttling orifices afiording communication between said exhaust pipeand chamber, a

stricting exhaust pipe, 9. pressure pulsation absorptlon chamber ofsubstantial Volume having an adjustable air vent therein, throttlingorifices affording communication between said exhaust pipe and chamber,a nozzle at the rear end of'the exhaust pipe downstream of saidthrottling orifices and a converging bypass exterior of said nozzleaifordin communication between said throttling orifices and a chamber tothe rear of sai nozzle.

In testimony whereof I afiix my signature.

ERNEST HUBY.

nozzle on the rear end of the exhaust pipe downstream of said throttlinorifices, a converging bypass exterior of said nozzle afi'ordincommunication between said throttling orifices and a chamber to the rearof said nozzle and a velocity equalizing passage connectebg to the rearend of the last mentioned chamr. 8. In a mufier, in combination, anon-re-

